Systems and methods for electrochemical deposition on a workpiece including removing contamination from seed layer surface prior to ecd

ABSTRACT

In one embodiment of the present disclosure, a method for electrochemical deposition on a workpiece includes (a) obtaining a workpiece including a feature; (b) depositing a first conductive layer in the feature; (c) moving the workpiece to an integrated electrochemical deposition plating tool configured for hydrogen radical H* surface treatment and electrochemical deposition; (d) treating the first conductive layer using a hydrogen radical H* surface treatment in a treatment chamber of the plating tool to produce a treated first conductive layer; and (e) maintaining the workpiece in the same plating tool and depositing a second conductive layer in the feature on the treated first conductive layer in an electrochemical deposition chamber of the plating tool.

BACKGROUND

In general, semiconductor devices are manufactured by fabricationprocesses forming electric circuits on a semiconductor substrate, suchas a silicon wafer. Metals, like copper, are commonly deposited on thesubstrate to form the electric circuits. A barrier metal layer can beused to prevent the diffusion of copper ions into the surroundingmaterials. A seed layer can be subsequently deposited on the barrierlayer to facilitate copper interconnect plating.

Recently, other metals, such as ruthenium and cobalt, have beenintroduced as seed layer materials to complement commonly used copperseed layers. Ruthenium, cobalt, and copper may be used separately or incombination to form seed layer stacks. One drawback of using rutheniumor cobalt as seed layer material is the tendency to oxidize quickly. Thenative oxide layer formed on a seed layer is not an optimal surface forinterconnect metallization plating, particularly for small-sizeddamascene fill features (such as vias and trenches), for example,features measuring less than 50 nm in width. Therefore, there areadvantages to reducing the oxide layer prior to initiating interconnectmetallization deposition processes.

Therefore, there exists a need for an improved process for reducing theoxide layer formed on a seed layer.

SUMMARY

The summary is provided to introduce a selection of concepts in asimplified form further described below in the Detailed Description. Thesummary is not intended to identify key features of the claimed subjectmatter, nor to be used as an aid in determining the scope of the claimedsubject matter.

In accordance with one embodiment of the present disclosure, a methodfor metal deposition on a workpiece is provided. The method includes (a)obtaining a workpiece including a feature; (b) depositing a firstconductive layer in the feature; (c) moving the workpiece to anintegrated electrochemical deposition plating tool configured forhydrogen radical H* surface treatment and electrochemical deposition;(d) treating the first conductive layer using a hydrogen radical H*surface treatment in a treatment chamber of the plating tool to producea treated first conductive layer; and (e) maintaining the workpiece inthe same plating tool and depositing a second conductive layer in thefeature on the treated first conductive layer in an electrochemicaldeposition chamber of the plating tool.

In accordance with another embodiment of the present disclosure, amethod for metal deposition on a workpiece is provided. The methodincludes (a) obtaining a workpiece including a feature having a featuresize may be of less than 50 nm; (b) depositing a seed layer in thefeature, wherein the seed layer is selected from the group consisting ofCVD cobalt, CVD ruthenium, and PVD, ALD, and CVD copper; (c) moving theworkpiece to an integrated electrochemical deposition plating toolconfigured for hydrogen radical H* surface treatment and electrochemicaldeposition; (d) treating the seed layer using a hydrogen radical H*surface treatment in a treatment chamber of the plating tool to producea treated first conductive layer; and (e) maintaining the workpiece inthe same plating tool and depositing a metal layer in the feature on theseed layer in an electrochemical deposition chamber of the plating tool.

In any of the methods described herein, treating the first conductivelayer may include treatment with hydrogen radicals H* generated in aplasma chamber.

In any of the methods described herein, wherein treating the firstconductive layer may include treatment with hydrogen radicals H*generated by a hot filament.

In any of the methods described herein, the first conductive layer maybe selected from the group consisting of cobalt, ruthenium, copper,nickel, copper manganese, copper cobalt, copper aluminum, copper nickel,and alloys thereof.

In any of the methods described herein, the first conductive layer maybe less than 300 Å.

In any of the methods described herein, the feature size may be lessthan 50 nm.

In any of the methods described herein, the feature further may includea barrier layer or an adhesion enhancement layer deposited prior todepositing the first conductive layer.

In any of the methods described herein, the hydrogen radical H* surfacetreatment may reduce oxides formed on the first conductive layer.

In any of the methods described herein, the hydrogen radical H* surfacetreatment may remove residual carbon from the surface of the firstconductive layer.

In any of the methods described herein, the hydrogen radical H* surfacetreatment may be conducted in a temperature range of room temperature toabout 250° C.

In any of the methods described herein, the hydrogen concentration inthe hydrogen radical H* chamber may be in the range of 2% to 10%.

In any of the methods described herein, the hydrogen concentration inthe hydrogen radical H* chamber may be 100%.

In any of the methods described herein, the hydrogen radical H* surfacetreatment may be conducted in a pressure range of 10 mT to 200 mT.

In any of the methods described herein, the hydrogen radical H* surfacetreatment may be conducted in a pressure range of atmospheric orsub-atmospheric.

In any of the methods described herein, the temperature of the hotfilament may be greater than 1000° C.

In any of the methods described herein, the hydrogen radical H* surfacetreatment may be conducted in a power range of 400 W to 1200 W.

In any of the methods described herein, further comprising annealing theworkpiece in the treatment chamber of the plating tool.

In any of the methods described herein, the workpiece may be exposed toa nitrogen environment after the deposition of a first conductive layerin the feature and before hydrogen radical H* surface treatment.

In any of the methods described herein, the workpiece may be exposed toa nitrogen environment after hydrogen radical H* surface treatment andbefore the deposition of a second conductive layer in the feature on thetreated first conductive layer.

In any of the methods described herein, oxidation of the firstconductive layer may be mitigated by exposure to a nitrogen environment.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thedisclosure will become more readily appreciated by reference to thefollowing detailed description, when taken in conjunction with theaccompanying drawings, wherein:

FIG. 1 schematically illustrates a cross-sectional representation of amicro-feature workpiece in accordance with one embodiment of the presentdisclosure;

FIGS. 2A-2E schematically illustrate a sequence of processescorresponding to an exemplary method of forming the workpiece of FIG. 1,as described herein;

FIG. 3 schematically illustrates a cross-sectional representation of amicro-feature workpiece in accordance with another embodiment of thepresent disclosure;

FIG. 4 schematically illustrates a hydrogen ion plasma chamber for usewith methods in accordance with embodiments of the present disclosure;

FIG. 5 schematically illustrates an electrochemical deposition platingtool for use with methods in accordance with another embodiment of thepresent disclosure;

FIGS. 6A and 6B are comparative TEM images of wafers plated according topreviously developed processes (FIG. 6A) and according to embodiments ofthe present disclosure (FIG. 6B);

FIGS. 7A, 7B, and 7C are comparative TEM images of wafers platedaccording to previously developed processes (FIGS. 7A and 7C) andaccording to embodiments of the present disclosure (FIG. 7B); and

FIG. 8 schematically illustrates another electrochemical depositionplating tool for use with methods in accordance with another embodimentof the present disclosure.

DETAILED DESCRIPTION

The present disclosure relates to methods for electrochemicallydepositing a conductive material, for example, a metal, such as copper(Cu), cobalt (Co), nickel (Ni) gold (Au), silver (Ag), manganese (Mn),tin (Sn), aluminum (Al), and alloys thereof, in features (such astrenches and vias, particularly in Damascene applications) of amicroelectronic workpiece.

Embodiments of the present disclosure are directed to workpieces, suchas semiconductor wafers, devices or processing assemblies for processingworkpieces, and methods of processing the same. The term “workpiece,”“wafer,” or “semiconductor wafer” means any flat media or article,including semiconductor wafers and other substrates or wafers, glass,mask, and optical or memory media, MEMS substrates, or any otherworkpiece having micro-electric, micro-mechanical, ormicroelectro-mechanical devices.

Methods in accordance with the present disclosure are generally directedto methods of forming micro-feature workpieces having improved seedlayers with oxide and carbon contamination removed. An exemplaryschematic of a workpiece constructed in accordance with methods of thepresent disclosure may be best understood by referring to FIG. 1. Theexemplary workpiece 20 generally includes a substrate 22 having abarrier layer 24, a seed layer 26 on the barrier layer 24, and a metallayer 30 on the seed layer 26. In accordance with embodiments of thepresent disclosure, the layer illustrated and described as a seed layer26 may be a first conducting layer, and the layer illustrated anddescribed as a metal layer 30 may be a second conducting layer.

Methods described herein are to be used for metal or metal alloydeposition in features of workpieces, including trenches and vias. Inone embodiment of the present disclosure, the process may be used insmall features, for example, features having a feature diameter of lessthan 50 nm. However, the processes described herein are applicable toany feature size. The dimension sizes discussed in the presentapplication are post-etch feature dimensions at the top opening of thefeature. In one embodiment of the present disclosure, Damascene featuresmay have a size of less than 50 nm. In another embodiment, Damascenefeatures may have a size of less than 40 nm. In another embodiment,Damascene features may have a size of less than 30 nm.

The descriptive terms “micro-feature workpiece” and “workpiece” as usedherein include all structures and layers previously deposited and formedat a given point in the processing, and is not limited to just thosestructures and layers as depicted in FIG. 1.

Although generally described as metal deposition in the presentapplication, the term “metal” also contemplates metal alloys. Suchmetals and metal alloys may be used to form seed layers or to fully orpartially fill the feature. As a non-limiting example, the alloycomposition ratio may be in the range of about 0.5% to about 6%secondary alloy metal, as compared to the primary alloy metal.

The workpiece 20 depicted in FIG. 2A provides a starting point forunderstanding some of the novel aspects of the disclosure. A method offorming a metal layer 30 on a workpiece 20 in accordance with oneembodiment of the present disclosure may be best understood by referringto the sequence of processes depicted in FIGS. 2A-2E to produce theworkpiece 20 depicted in FIG. 1. The illustrated method generallyincludes providing a substrate layer 22 (FIG. 2A), depositing a barrierlayer 24 on the substrate layer 22 (FIG. 2B), depositing a seed layer 26on the barrier layer 24 (FIG. 2C) including native oxide layer 28 on theseed layer, reducing oxides on the seed layer 26 and cleaning the seedlayer 26 of impurities (FIG. 2D) to provide a treated seed layer 26 (seeFIG. 2E), and depositing a metal layer 30 on the cleaned seed layer (26and 28) (return to FIG. 1).

Comparing FIGS. 2A and 2B, an exemplary deposition of the barrier layer24 on the substrate layer 22 is illustrated. The substrate layer 22 maybe any suitable substrate layer including, but not limited to, a siliconoxide layer, a silicate layer, a low-K dielectric layer, or an air gapsilicon oxide layer. The barrier layer 24 limits metal diffusivity(e.g., copper diffusivity) to chemically isolate a metal conductor 30(see FIG. 1) from the substrate 22. Suitable barrier layer materialsgenerally have low electrical conductivity, and may include, but are notlimited to, tantalum nitride, titanium nitride, manganese, tungsten,tungsten carbide, tungsten nitride, manganese silicate, and manganesenitride.

The conventional fabrication of metal interconnects may include asuitable deposition of a barrier layer on the dielectric material toprevent the diffusion of copper into the dielectric material. Suitablebarrier layers include, for example, Ta, Ti, TiN, TaN, Mn, or MnN.Barrier layers are typically used to isolate copper or copper alloysfrom dielectric material. However, in the case of other metalinterconnects, diffusion may not be a problem and a barrier layer maynot be required. In the case of a cobalt seed layer, a barrier layer maynot be needed. Instead, a TiN adhesion enhancement liner may be used toenhance adhesion between the substrate and the cobalt seed layer.

Although the exemplary workpiece 20 illustrated in FIG. 1 includes botha barrier layer 24 and a seed layer 26, the barrier layer 24 may beoptional. In accordance with embodiments of the present disclosure, thebarrier layer and the seed layer may be combined into one layer. As anon-limiting example, ruthenium may be co-deposited with tantalum toform a combined barrier and seed layer. The barrier characteristics ofthe example are generally determined by the percentage of tantalum inthe tantalum-ruthenium alloy, as one non-limiting example, from about 1to about 10 percent tantalum. Therefore, in accordance with embodimentsof the present disclosure, the first conducting layer of a workpiece maybe a combination barrier and seed layer, such as a ruthenium tantalumlayer, and the second conducting layer may be a metal layer, such as acopper layer.

One drawback of using a barrier layer in a metal plating process is adifficulty in plating metal, such as copper, on typical barrier layermaterials. Therefore, an intermediate seed layer can be used to initiatethe nucleation and improve metal adhesion for plating, as described withreference to FIG. 2C below. As described above, a combination seed andbarrier layer may also be suitable for plating, in accordance withembodiments of the present disclosure.

The barrier layer 24 of the illustrated embodiment is formed on asubstrate 22, as depicted in FIG. 1; however, barrier layers formed onsubstrate layers of workpieces are also within the scope of the presentdisclosure. As non-limiting examples, barrier layers can be formed ongate, source, and drain regions of a workpiece. Accordingly, the terms“substrate” and “substrate layer” can be used interchangeably throughoutthe present disclosure.

The barrier layer deposition may be followed by an optional seed layer26 deposition. Referring to FIG. 2C, an exemplary deposition of the seedlayer 26 on the barrier layer 24 is illustrated. As seen in FIG. 2C, theseed layer 26 forms a native oxide layer 28 immediately afterdeposition.

In the case of depositing metal in a feature, there are several optionsfor the seed layer. For example, the seed layer may be (1) aconventional seed layer (as a non-limiting example, a PVD copper seedlayer). The seed layer may be a metal layer, such as copper, cobalt,nickel, gold, silver, manganese, tin, aluminum, ruthenium, and alloysthereof. The seed layer may also be (2) a stack film of a liner layerand a seed layer (as a non-limiting example, a CVD Co or Ru liner layerand a PVD copper seed layer), or (3) a secondary seed layer (as anon-limiting example, a CVD or ALD Co or Ru secondary seed layer). Othermethods of depositing exemplary seed layers are also contemplated by thepresent disclosure.

In one non-limiting example, a typical seed layer is a copper seedlayer. As other non-limiting examples, the seed layer may be a copperalloy seed layer, such as copper manganese, copper cobalt, copperaluminum, and copper nickel alloys. In the case of depositing copper ina feature, there are several exemplary options for the seed layer.First, the seed layer may be a PVD copper seed layer. The seed layer mayalso be formed by using other deposition techniques, such as CVD or ALD.

A liner layer is a material used in between a barrier layer and a seedlayer to mitigate discontinuous seed issues and improve adhesion of theseed layer. Liners are typically noble metals such as Ru, Pt, Pd, andOs, but the list may also include Co and Ni. Currently, CVD Ru and CVDCo are common liners; however, liner layers may also be formed by usingother deposition techniques, such as PVD or ALD. The thickness of theliner layer may be in the range of around 5 Å to 50 Å for Damasceneapplications.

A secondary seed layer is similar to a liner layer and is typicallyformed from the same metals and the same deposition processes. Thedifference is the secondary seed layer serves as the seed layer, whereasthe liner layer is an intermediate layer between the barrier layer andthe seed layer.

The seed layer deposit may be thermally treated or annealed at atemperature between about 100° C. to about 500° C. in a forming gasenvironment (e.g., 3%-5% hydrogen in nitrogen or 3%-5% hydrogen inhelium) to remove any surface oxides, increase the density of thesecondary seed or liner layer, and improve the surface properties of thedeposit. The liner or secondary seed deposit may additionally bepassivated by the soaking in gaseous nitrogen (N2 gas) or otherpassivating environments to prevent or mitigate further surfaceoxidation.

Suitable seed layers are generally formed by CVD or PVD processes asdescribed above, but may also be formed by wet seed plating. Wet seedplating is generally known in the art as a non-traditional platingtechnique using an alkaline plating bath (as opposed to an acidicplating bath) to plate a thin conformal “wet seed” layer of metal beforegap filling metal using a traditional acid plating bath. An exemplaryworkpiece plated using a “wet seed” metal plating process is shown inFIG. 3. The exemplary workpiece generally includes a substrate 22 havinga barrier layer 24, a seed layer 26 on the barrier layer 24, a wet seedmetal layer 40 on the seed layer 26 and a subsequent metal layer 42plated on the wet seed layer 40. In one embodiment of the presentdisclosure, the wet seed layer may have a thickness in the range ofabout 1 to about 5 nanometers.

Referring to FIG. 1, after a seed layer has been deposited (such as oneof the non-limiting examples of PVD copper seed, PVD copper seedincluding CVD Ru liner, or CVD Ru secondary seed, or another depositionmetal or metal alloy, layer combination, or deposition technique), thefeature may include a metal layer 30 deposited after the seed layer. Insome embodiments, the metal layer 30 may be a copper metallizationlayer. In other embodiment, the metal layer 30 may be a cobaltmetallization layer.

In previously developed processes, a copper seed layer was formed, forexample, using a PVD process, prior to a copper plating process. Becauseof PVD process limitations, copper seed layers usually deposit a certainthickness of at least 20 nanometers to have step coverage on the featurewall and be reliable and effective as seed layers. Such thickness oftenresults in an enhanced overhang at the feature opening. The overhangimpedes electrochemically plating copper using a copper damascene fillprocess in smaller-sized features, for example, features having a widthvalue on the order of less than about 1 micron, or more preferably, lessthan about 50 nanometers.

Recently, other metals besides copper, such as ruthenium and cobalt havebeen introduced as suitable alternatives seed layer material to a copperseed layer. Advantageously, the ruthenium and cobalt seed layers can beformed by CVD or ALD processes, resulting in a nearly conformal layerwith a smooth surface. In addition, embodiments of the presentdisclosure provide advantages in plating over copper seed layers toallow for a better interface between the plated copper and copper seedsdeposited by CVD or ALD processes.

One drawback of the seed layer, as mentioned above, is the tendency tooxidize quickly, and such oxidation may degrade metal (e.g., copper)deposition on the seed layer. Another drawback is that an oxidizedsurface tends to increase defects and may degrade the reliability of theinterconnect. Such oxides should therefore be reduced prior to metaldeposition, for example, in the exemplary processes illustrated in FIGS.2C-2E. In previously developed processes, oxide reduction included oneor more of a high-temperature, reducing gas anneal, an electrolyticcleaning process, for example, using a strong acid and an electriccharge to reduce the oxide layer, and other processes for providing asubstantially fresh metal surface.

As mentioned above, oxide reduction and removal of contaminants on theseed layer can be achieved by subjecting the seed layer 26 to anannealing process in the presence of a reducing gas. One suitableexample of a reducing gas is hydrogen. The reducing gas may be mixedwith an inert gas (for example, nitrogen, argon, or helium), wherein thereducing gas amount may be in the range of about 2 to about 100 percentof the mixture. As a non-limiting example, the reducing gas may be amixture of 2% hydrogen and 98% helium. In one suitable oxide reductionprocess, the reducing gas anneal is performed at a temperature of about300-400 degrees C. for about 2-5 minutes. The hydrogen in the reducinggas combines with the oxygen in the oxides to form water as a by-productof the oxide reduction process.

The drawback of the traditional approach of annealing in the presence ofa reducing gas is the annealing temperature of greater than 300° C.,higher than the thermal budget of thin seed layer and therefore cancause agglomeration, de-wetting, or beading of the seed material,rendering it discontinuous.

In accordance with embodiments of the present disclosure, surfacetreatment can be achieved using a low temperature surface treatmentmethod so as to maintain the integrity and continuity of the depositedseed layer and minimize damage to the seed layer. Referring to FIG. 2D,in one embodiment of the present disclosure, the seed layer is treatedwith hydrogen radicals H*. The hydrogen radicals H* is used to reducemetal oxides back to metal and covert the oxides to water. The hydrogenradical H* can also be used to clean contaminants from the seed layersurface, such as carbon.

In accordance with embodiments of the present disclosure, the hydrogenradicals H* may be generated using a plasma chamber, using ahot-filament radical source, or a combination of both. The hydrogenradicals H* can be used to uniformly reduce oxides and clean the seedlayer surface in the feature.

Advantageous effects of hydrogen radical H* surface treatment inaccordance with embodiments of the present disclosure include reducedagglomeration of the conductor layers and/or reduced changes to theintrinsic properties of the seed layer were typically caused by hightemperature treatments in previously developed processes. Anotheradvantageous effect of surface treatment includes enhances nucleation ofthe plated conductor as a result of the surface treatment to reduceoxygen and other contaminants.

Referring to FIG. 4, hydrogen radical H* generation in a plasma chamberwill now generally be described in detail. Plasma in micro-processing isused to generate ions and radicals through inelastic collisions betweenneutral molecules and high-energy electrons. The generated ions areaccelerated by an electric field toward the workpiece to sputter theoxides and contaminants away.

In one embodiment of the present disclosure, in the plasma chamber,hydrogen ion radical plasma is created remotely. The hydrogen ions arefiltered in applicator tube by an ion filter. The reactive H* radicalsenter the chamber body. Hydrogen radicals H* pass through an optimizedshowerhead for lowest on-wafer non-uniformity for metal oxide reduction.The heated pedestal in the chamber maximizes process efficiency withoptimized process variables.

The advantageous effect of allowing the H* radical in the plasma, but tofilter out the ions, is a plasma that can react with carbon and oxideimpurities on the sides of the feature. In contrast, ions are generallydirected toward the bottom of the feature, and therefore, sputter thefilm at the bottom only.

The primary purpose for plasma applications is to generate ions andradicals through the inelastic collisions between high energy electronsand neutral molecules in the gas phase. The generated ions areaccelerated by an electric field toward the workpiece and sputter thesurface. The sputtering is purely a physical process and sputtering canalso be used for etching in addition sputter deposition. Sputter-basedcleaning is generally undesirable because it tends to remove seed layermaterials, particularly at the bottoms of the features. In addition,ions are incapable of effectively cleaning the sides of the features asa result of the trajectory nature of the charged ions under theinfluence of the electrical field.

Radicals, on other hand, are species with an unshared electro pair andreactive. Therefore, radicals elicit a spontaneous chemical reaction.Because of a lack of charge, however, radicals do not accelerate towardthe workpiece. Therefore, radicals can be used to clean the side wallsand the bottoms of the features.

H* radicals can also be generated by hot-filament source, for example, arefractory metal wire that is heated to a high temperature. At thesurface of the wire, the dissociation of molecules is catalyticallypromoted to form radicals. The radical formation process is a pyrolyticprocess and therefore eliminates energetically charged ions that mightdamage the seed layer materials.

In a hot-filament radical source, a hot filament, such as a tungstenwire can be electrically heated at a high temperature, e.g., above 1000°C., 1200° C., or in the range of 1200°−2000° C. in a hydrogen ambient togenerate hydrogen radicals H*. A pressure differential can be used todrive the hydrogen radicals H* to the seed layer surface.

Regardless of the source of hydrogen radicals H*, the treatment can beconducted at low temperature, as compared to a high-temperature surfaceanneal to reduce oxides. In one embodiment of the present disclosure,hydrogen radical H* surface treatment may be achieved using a processingtemperature in the range of room temperature to 300° C. In anotherembodiment of the present disclosure, surface treatment may be achievedusing a processing temperature in the range of room temperature to 200°C. In one embodiment, the processing temperature is room temperature. Inanother embodiment, the processing temperature is 180° C. In anotherembodiment of the present disclosure, surface treatment may be achievedusing a processing temperature in the range of room temperature to 100°C. In another embodiment of the present disclosure, surface treatmentmay be achieved using a processing temperature in the range of roomtemperature to 50° C. Low temperature surface treatment may be effectivein reducing damage to the seed layer.

Experimental results have shown hydrogen radical H* reduction of oxidesis achieved at room temperature. However, a temperature elevation, forexample, to 180° C. improves the removal of carbon impurities from theseed layer.

In some embodiments of the present disclosure, a suitable pressure rangefor the hydrogen radical source H* may be in the range of 10 mT to 200mT. The advantageous effect of operating the chamber at a pressurehigher than atmospheric pressure is contaminants can be kept fromentering the plating chamber. In other embodiments, the pressure in theplasma chamber may be sub-atmospheric or atmospheric.

In some embodiments of the present disclosure, a suitable hydrogenradical H* concentration is in the range of about 2% to 10%. Theremainder of the environment may be helium or another inert gas. Inother embodiments, the hydrogen radical H* may not require a carriergas, having a hydrogen radical H* concentration of 100% or close to100%.

In some embodiments of the present disclosure, a suitable power rangefor the hydrogen radical source H* may be in the range of 400 W to 1200W.

After surface treatment by hydrogen radicals H*, a short processingwindow between surface treatment and electrochemical deposition,re-oxidation of the seed layer surface is significantly reduced.Accordingly, in some embodiments of the present disclosure, the timerange between seed layer surface treatment and metallization layerdeposition is less than 60 seconds. In other embodiments, the time rangemay be less than 30 seconds. In some embodiments, re-oxidation of theseed layer may be mitigated by storing the workpiece in a nitrogenenvironment (or another passivating environment) before plasma surfacetreatment, after plasma surface treatment, or during other intervals inworkpiece processing.

In comparison, typical a plating window after a copper seed depositionprocess is in the range of about 12-24 hours, generally considered bythe industry to be an acceptable time period for plating interconnectmetal on a copper seed layer. Moreover, copper seed layer surfacetreatment in accordance with the processing methods described herein mayhave the effect of improving adhesion, reducing defects, improvinginterconnect reliability, and other properties for subsequent coppermetallization layers.

To achieve the short processing window, advances have been made to theplating tool. Referring to FIG. 5, an exemplary plating tool for usewith methods described herein in shown. In the illustrated embodiment, adeck view of an exemplary RAIDER® plating tool manufactured by APPLIEDMaterials, Inc., is provided including several plating cells,spin-rinse-dry chambers, and a hydrogen radical H* generation chamber.By including the hydrogen radical H* generation chamber in the platingtool, the time range between seed layer surface treatment andmetallization layer deposition can be 60 seconds or less.

Another exemplary embodiment of an exemplary plating tool, commonlyknown as the MUSTANG® tool manufactured by APPLIED Materials, Inc., isshown in FIG. 8. The tool of FIG. 8 includes modules or subsystemswithin an enclosure 122. Wafer or substrate containers 124, such as FOUP(front opening unified pod) containers, may be docked at a load/unloadstation 126 at the front of the enclosure 122. The subsystems used mayvary with the specific manufacturing processes performed by the system120. In the illustrated embodiment, the system 120 includes a frontinterface 128 which may provide temporary storage for wafers to be movedinto or out of the system 120, as well as optionally providing otherfunctions. As non-limiting examples, the system 120 may include ananneal module 130, a hydrogen radical H* generation chamber, a rinse/drymodule 132, a ring module 140, and electroplating chambers 142, whichmay be sequentially arranged within the enclosure 122 behind the frontinterface 128. Robots move the wafers between the subsystems.

In some embodiments of the present disclosure, the tool may have anambient air environment between chambers. In other embodiments, the toolmay have an nitrogen environment in the enclosure between chambers tomitigate oxidation of the seed layer before plasma surface treatment,after plasma surface treatment, or during other intervals in workpieceprocessing.

In some embodiments of the present disclosure, the tool may includeseparate annealing and hydrogen radical H* generation chambers. In otherembodiments of the present disclosure, the hydrogen radical H*generation may occur in the same chamber as is used for an annealingprocess. Although the same chamber may be used for both processes, theprocesses will occur separately in the workpiece manufacturing process,and not at the same time. To accommodate both processes, the chamberwill have both hydrogen radical H* generation capabilities and annealingcapabilities. In one embodiment, the chamber accommodates a temperaturerange from room temperature to 300° C. or room temperature to 400° C.

The combination of hydrogen radical H* generation and annealing in oneprocessing chamber reduces that manufacturing site foot print of thetool and provides for annealing at high temperature and high vacuum,which may prove to be of benefit to the seed layer.

In some embodiments of the present disclosure, the metallization layermay be a copper metallization layer. In other embodiments of the presentdisclosure, the metallization layer may be a cobalt metallization layer.The metal options of the seed and metallization layers are describedabove. Embodiments of the present disclosure include, for example, acobalt seed layer and a cobalt metallization layer and a copper seedlayer and a copper metallization layer. In these non-limiting examples,there is no distinguishable interface between seed and metallizationlayers upon reduction of the oxide layer as described herein.

In addition, cobalt and nickel are emerging as alternatives to copperinterconnect metallization. For those metals, cobalt or nickel seeds maybe used.

Example 1 Hydrogen Plasma Treated Wafer

Treatment and control wafers each received a 40A PVD TaN barrier layerand a 25A CVD Co seed. Wafers were left for 24 hours at ambienttemperature and pressure. The treatment wafer was treated with hydrogenplasma (about 2% H2 in He) for 60 seconds at 250 C set pointtemperature. The queue time between plasma treatment and plating wasless than one hour. The treated wafer was stored in a nitrogen purgedstorage pod for transportation and storage.

The control wafer was not stored in a nitrogen purged storage pod fortransportation and storage and was not treated using H2 plasma.

Both plasma treated Co wafer and the control Cu wafers were plated usinga charge of 2 A·min of ECD Seed Cu followed by an annealing process at250° C. for 1 minute. All wafers were capped with conventional acidchemistry NP5200.

Referring to FIGS. 6A and 6B, TEM images are provided comparing plasmatreated and non-treated Co seed surfaces. Surface oxidation appears onthe control (untreated) CVD Co layer (see FIG. 6A), whereas there is aclean interface between the plasma treated CVD Co film and the plated Culayer (see FIG. 6B).

Example 2 Tem Images for 5× Trenches

A comparison of Super ECD Cu/Co (no hydrogen plasma), Super ECD Cu/Co(with hydrogen plasma), and Super ECD Cu/Cu seed control results areprovided in FIGS. 7A, 7B, and 7C.

For the untreated Co film, voids are seen hear the interface of the seedand the Cu fill. Wafers with hydrogen plasma treated CVD Co film andcontrol showed a good interface between the seed layer and the Cu fill.

While illustrative embodiments have been illustrated and described,various changes can be made therein without departing from the spiritand scope of the disclosure.

1. A method for metal deposition on a workpiece, the method comprising:receiving a workpiece in an integrated electrochemical depositionplating tool configured for hydrogen radical H* surface treatment andelectrochemical deposition, the workpiece including a nonmetallicsubstrate having a dielectric layer disposed over a substrate and acontinuous first conductive layer disposed by CDV, ALD, or PVD on thedielectric layer and having one or more microfeatures comprisingrecessed structures having a feature size of less than 50 nm, whereinthe thickness of the first conductive layer is less than 300 Å; treatingthe first conductive layer using a hydrogen radical H* surface treatmentin a treatment chamber of the plating tool to produce a treated firstconductive layer; and maintaining the workpiece in the same plating tooland depositing a second conductive layer in the feature on the treatedfirst conductive layer in an electrochemical deposition chamber of theplating tool.
 2. The method of claim 1, wherein treating the firstconductive layer includes treatment with hydrogen radicals H* generatedin a plasma chamber.
 3. The method of claim 1, wherein treating thefirst conductive layer includes treatment with hydrogen radicals H*generated by a hot filament.
 4. The method of claim 1, wherein the firstconductive layer is selected from the group consisting of cobalt,ruthenium, copper, nickel, copper manganese, copper cobalt, copperaluminum, copper nickel, and alloys thereof. 5-6. (canceled)
 7. Themethod of claim 1, wherein the feature further includes a barrier layeror an adhesion enhancement layer deposited prior to the deposition ofthe first conductive layer.
 8. The method of claim 1, wherein thehydrogen radical H* surface treatment reduces oxides formed on the firstconductive layer.
 9. The method of claim 1, wherein the hydrogen radicalH* surface treatment removes residual carbon from the surface of thefirst conductive layer.
 10. The method of claim 1, wherein the hydrogenradical H* surface treatment is conducted in a temperature range of roomtemperature to about 250° C.
 11. The method of claim 1, wherein thehydrogen concentration in the hydrogen radical H* chamber is in therange of 2% to 10%.
 12. The method of claim 1, wherein the hydrogenconcentration in the hydrogen radical H* chamber is 100%.
 13. The methodof claim 1, wherein the hydrogen radical H* surface treatment isconducted in a pressure range of 10 mTorr to 200 mTorr.
 14. The methodof claim 1, wherein the hydrogen radical H* surface treatment isconducted in a pressure range of atmospheric or sub-atmospheric.
 15. Themethod of claim 3, wherein the temperature of the hot filament isgreater than 1000° C.
 16. The method of claim 2, wherein the hydrogenradical H* surface treatment is conducted in a power range of 400 W to1200 W.
 17. (canceled)
 18. A method for metal deposition on a workpiece,the method comprising: receiving a workpiece in an integratedelectrochemical deposition plating tool configured for hydrogen radicalH* surface treatment and electrochemical deposition, the workpieceincluding a nonmetallic substrate having a dielectric layer disposedover a substrate and a continuous first conductive layer disposed on thedielectric layer and having one or more microfeatures comprisingrecessed structures; exposing the workpiece to a nitrogen environment;treating the first conductive layer that has been exposed to a nitrogenenvironment using a hydrogen radical H* surface treatment in a treatmentchamber of the plating tool to produce a treated first conductive layer;and maintaining the workpiece in the same plating tool and depositing asecond conductive layer in the feature on the treated first conductivelayer in an electrochemical deposition chamber of the plating tool. 19.A method for metal deposition on a workpiece, the method comprising:receiving a workpiece in an integrated electrochemical depositionplating tool configured for hydrogen radical H* surface treatment andelectrochemical deposition, the workpiece including a nonmetallicsubstrate having a dielectric layer disposed over a substrate and acontinuous first conductive layer disposed on the dielectric layer andhaving one or more microfeatures comprising recessed structures;treating the first conductive layer using a hydrogen radical H* surfacetreatment in a treatment chamber of the plating tool to produce atreated first conductive layer; exposing the workpiece to a nitrogenenvironment after hydrogen radical H* surface treatment and before thedeposition of the second conductive layer in the feature on the treatedfirst conductive layer; and maintaining the workpiece in the sameplating tool and depositing a second conductive layer in the feature onthe treated first conductive layer in an electrochemical depositionchamber of the plating tool.
 20. The method of claim 18, whereinoxidation of the first conductive layer is mitigated by exposure to anitrogen environment.
 21. A method for metal deposition on a workpiece,the method comprising: receiving a workpiece in an integratedelectrochemical deposition plating tool configured for hydrogen radicalH* surface treatment and electrochemical deposition, the workpieceincluding a nonmetallic substrate having a dielectric layer disposedover a substrate and a continuous seed layer disposed on the dielectriclayer, the seed layer selected from the group consisting of CVD cobalt,CVD ruthenium, and PVD, ALD, and CVD copper, and the workpiece includingone or more microfeatures comprising recessed structures having afeature size of less than 50 nm, and wherein the thickness of the seedlayer is less than 300 Å; treating the seed layer using a hydrogenradical H* surface treatment in a treatment chamber of the plating toolto produce a treated first conductive layer; and maintaining theworkpiece in the same plating tool and depositing a metal layer in thefeature on the seed layer in an electrochemical deposition chamber ofthe plating tool.
 22. The method of claim 21, wherein the featureincludes a barrier layer or an adhesion enhancement layer.